1. Field of the Invention
This invention relates to culture plates and, more particularly, to culture plates which have an element for preventing splashing of liquids contained therein.
2. Description of the Prior Art
The use of culture plates, traditionally known as Petri dishes or culture dishes, in growing or culturing bacteria, eucaryotic cells, or other organisms is well known. A typical culture plate is a clear plastic structure including a cylindrical, open-topped base and a complementary or mating lid configured to sit on and close off the base. Prior art patents in this field include U.S. Pat. Nos. 3,248,302; 3,677,904; 3,751,341; 4,299,921; 4,743,556; 4,801,548 and 5,021,351.
A number of culture plates are often used at one time in a batch operation. Some culture plates contain multiple wells in one device. Each culture plate will carry a desired liquid growth medium. The plates are placed on a larger tray, and the tray is moved into and out of an incubator, typically by hand. During this handling, the tray may stick in the incubator rack or may bump into the side or rear walls of the incubator and exert a jarring force on the culture plates carried by the tray. This jarring force on a tray, or even normal handling of a tray, may cause movement of the liquid media within each culture plate and result in the liquid media sloshing onto the lid or base sidewall and splashing over the top edge of the base sidewall. When liquid thus travels to the outer, non-sterile areas of the culture plate, a path is formed which permits bacteria growth to travel to the inside areas of the culture plate and to contaminate the contents therein. Clearly such contamination of an otherwise sterile culture plate is unacceptable in practice. Alternatively, media from inside the plate can splash out of the plate, down the outside sidewall and into the incubator environment. Such media leakage provides nutrients for bacteria or fungi to replicate outside the culture plate and further contaminate the otherwise clean environment inside an incubator.
Individual culture plates are also handled by a user and movement of an individual culture plate can result in the splashing of the liquid media and the same contamination problem discussed above. In addition, if the culture plate is growing or includes a pathogenic or radioactive material, or the like, it is highly undesirable for this material to splash out of the culture plate and onto the user handling the culture plate or into the incubator environment.
Therefore, it is an object of the present invention to provide a culture plate in which flows of liquid over the top of the base sidewall are eliminated or greatly reduced for all but extreme movement of the culture plate. It is another object of the present invention to provide such a fluid flow prevention feature in either a specially designed culture plate or in a modification to existing culture plates. It is a further object of the present invention to provide such a culture plate or modification in an arrangement which is reliable, easy to use, and inexpensive to manufacture.